Appearing before magistrates in Westminster today, May-Bowles - an activist also known as Jonnie Marbles - pleaded guilty to charges of assault and causing harassment, alarm or distress in a public place.

Murdoch's wife Wendi Deng, who was sitting behind the billionaire as he gave evidence to the MPs, leapt up and pushed the assailant away. She then hit May-Bowles with the plate as he was taken away by police.

At the time, May-Bowles said that he attacked the 80-year-old billionaire because he "had no faith in the parliamentary process" and "wanted to see some kind of justice done".

The committee hearing was suspended as police apprehended May-Bowles and took him out of the Wilson Room in Portcullis House at Westminster.

When the hearing resumed after the incident, Labour MP Tom Watson concluded his questioning by telling the News Corporation boss: "Your wife has a very good left hook."

"If you're of sound mind, you might quite reasonably ask what possessed me to smuggle a shaving foam pie into Portcullis House and throw it at (though, alas, not into) the face of one of the world's richest and most powerful men. I didn't do it because I wanted more Twitter followers. Simply put, I did it for all the people who couldn't," he wrote in The Guardian.